I want something that gives the same ground clearance as the stock 16's maybe a little lower but also fill up the wheel well. Even though the stock tires are 225, you can run 245 without any problems? I haven't tried any different sizes so I wouldn't know.

And to be honest, I don't know a thing about offset. I think it's something to do with how far the rim comes out of the brakes. Also what offset would be good to have a flush look between the wheels and fender?